EN 60309-1:1999

SLOVENSKI STANDARD
01-april-2000
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SIST EN 60309-1:1999
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Plugs, socket-outlets and couplers for industrial purposes -- Part 1: General
requirements
Stecker, Steckdosen und Kupplungen für industrielle Anwendungen -- Teil 1: Allgemeine
Anforderungen
Prises de courant pour usages industriels -- Partie 1: Règles générales
Ta slovenski standard je istoveten z: EN 60309-1:1999
ICS:
29.120.30 9WLþLYWLþQLFHVSRMNH Plugs, socket-outlets,
couplers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME CEI
INTERNATIONALE IEC
60309-1
INTERNATIONAL
Quatrième édition
STANDARD
Fourth edition
1999-02
Prises de courant pour usages industriels –
Partie 1:
Règles générales
Plugs, socket-outlets and couplers
for industrial purposes –
Part 1:
General requirements
 IEC 1999 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun procédé, any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photo-copie et les including photocopying and microfilm, without permission in
microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
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CODE PRIX
Commission Electrotechnique Internationale
XC
PRICE CODE
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

60309-1  IEC:1999 – 3 –
CONTENTS
Page
FOREWORD . 5
INTRODUCTION .7
Clause
1 Scope . 9
2 Definitions. 9
3 Normative references . 17
4 General. 19
5 Standard ratings.21
6 Classification . 21
7 Marking. 23
8 Dimensions . 29
9 Protection against electric shock . 29
10 Provision for earthing . 31
11 Terminals. 33
12 Interlocks . 43
13 Resistance to ageing of rubber and thermoplastic material . 45
14 General construction . 47
15 Construction of socket-outlets . 47
16 Construction of plugs and connectors . 51
17 Construction of appliance inlets . 53
18 Degrees of protection . 55
19 Insulation resistance and dielectric strength. 59
20 Breaking capacity. 61
21 Normal operation. 65
22 Temperature rise. 67
23 Flexible cables and their connection . 71
24 Mechanical strength . 77
25 Screws, current-carrying parts and connections . 83
26 Creepage distances, clearances and distances through sealing compound . 89
27 Resistance to heat, fire and tracking. 91
28 Corrosion and resistance to rusting . 95
29 Conditional short-circuit current withstand test. 97
30 Electromagnetic compatibility . 101
Figures. 103
Annex A – Guidance and description of test apparatus. 139

60309-1  IEC:1999 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_________
PLUGS, SOCKET-OUTLETS AND COUPLERS FOR INDUSTRIAL PURPOSES –
Part 1: General requirements
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60309-1 has been prepared by subcommittee 23H: Industrial plugs
and socket-outlets, of IEC technical committee 23: Electrical accessories.
This fourth edition cancels and replaces the third edition published in 1997 and constitutes a
technical revision.
The text of this standard is based on the following documents:
FDIS Report on voting
23H/88/FDIS 23H/91/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
Annex A forms an integral part of this standard.

60309-1  IEC:1999 – 7 –
INTRODUCTION
International Standard IEC 60309 is divided into several parts:
Part 1: General requirements, comprising clauses of a general character.
Subsequent parts: Particular requirements dealing with particular types. The clauses of these
particular requirements supplement or modify the corresponding clauses in part 1. Where the
text of subsequent parts indicates an "addition" to or a "replacement" of the relevant
requirement, test specification or explanation of part 1, these changes are made to the relevant
text of part 1, which then becomes part of the standard. Where no change is necessary, the
words "This clause of part 1 is applicable" are used.

60309-1  IEC:1999 – 9 –
PLUGS, SOCKET-OUTLETS AND COUPLERS FOR INDUSTRIAL PURPOSES –
Part 1: General requirements
1 Scope
This standard applies to plugs and socket-outlets, cable couplers and appliance couplers, with
a rated operating voltage not exceeding 690 V d.c. or a.c. and 500 Hz a.c., and a rated current
not exceeding 250 A, primarily intended for industrial use, either indoors or outdoors.
The list of preferred ratings is not intended to exclude other ratings, requirements for which are
under consideration.
This standard applies to plugs and socket-outlets, cable couplers and appliance couplers,
hereinafter referred to as accessories, for use when the ambient temperature is normally within
the range of –25 °C to +40 °C. These accessories are intended to be connected to cables of
copper or copper alloy only.
The use of these accessories on building sites and for agricultural, commercial and domestic
applications is not precluded.
Socket-outlets or appliance inlets incorporated in or fixed to electrical equipment are within the
scope of this standard. This standard also applies to accessories intended to be used in extra-
low voltage installations.
This standard does not apply to accessories primarily intended for domestic and similar general
purposes.
In locations where special conditions prevail, for example on board ship or where explosions
are liable to occur, additional requirements may be necessary.
2 Definitions
Where the terms voltage and current are used, they imply the d.c. or the a.c. r.m.s. values.
For the purpose of this part of IEC 60309, the following definitions apply.
The application of accessories is shown in figure 1.
2.1
plug and socket-outlet
a means enabling the connection at will of a flexible cable to fixed wiring. It consists of two
parts:
60309-1  IEC:1999 – 11 –
2.1.1
socket-outlet
the part intended to be installed with the fixed wiring or incorporated in equipment.
A socket-outlet may also be incorporated in the output circuit of an isolating transformer
2.1.2
plug
the part integral with or intended to be attached directly to one flexible cable connected to the
equipment or to a connector
2.2
cable coupler
a means enabling the connection at will of two flexible cables. It consists of two parts:
2.2.1
connector
the part integral with or intended to be attached to one flexible cable connected to the supply
NOTE – In general, a connector has the same contact arrangement as a socket-outlet.
2.2.2
plug
the part integral with or intended to be attached to one flexible cable connected to the
equipment or to a connector
NOTE – The plug of a cable coupler is identical to the plug of a "plug and socket-outlet".
2.3
appliance coupler
a means enabling the connection at will of a flexible cable to the equipment. It consists of two
parts:
2.3.1
connector
the part integral with, or intended to be attached to, one flexible cable connected to the supply
NOTE – In general, the connector of an appliance coupler is identical to the connector of a cable coupler.
2.3.2
appliance inlet
the part incorporated in, or fixed to, the equipment or intended to be fixed to it
NOTE – In general, an appliance inlet has the same contact arrangement as a plug.
2.4
rewirable plug or connector
an accessory so constructed that the flexible cable can be replaced
2.5
non-rewirable plug or connector
an accessory so constructed that the flexible cable cannot be separated from the accessory
without making it permanently useless
2.6
mechanical switching device
a switching device designed to close and open one or more electric circuits by means of
separable contacts
60309-1  IEC:1999 – 13 –
2.7
switched socket-outlet
a socket-outlet with an associated switching device to disconnect the supply from the socket-
outlet contacts
2.8
integral switching device
a mechanical switching device constructed as a part of an accessory covered by this standard
2.9
interlock
a device, either electrical or mechanical, which prevents the contacts of a plug from becoming
live before it is in proper engagement with a socket-outlet or connector, and which either
prevents the plug from being withdrawn while its contacts are live or makes the contacts dead
before separation
2.10
retaining device
a mechanical arrangement which holds a plug or connector in position when it is in proper
engagement, and prevents its unintentional withdrawal
2.11
rated current
the current assigned to the accessory by the manufacturer
2.12
insulation voltage
the voltage assigned to the accessory by the manufacturer and to which dielectric tests,
clearances and creepage distances are referred
2.13
rated operating voltage
the nominal voltage of the supply for which the accessory is intended to be used
2.14
basic insulation
the insulation necessary for the proper functioning of the accessory and for basic protection
against electric shock
2.15
supplementary insulation (protective insulation)
an independent insulation provided in addition to the basic insulation, in order to ensure
protection against electric shock in the event of a failure of the basic insulation
2.16
double insulation
insulation comprising both basic insulation and supplementary insulation
2.17
reinforced insulation
an improved basic insulation with such mechanical and electrical qualities that it provides the
same degree of protection against electric shock as double insulation

60309-1  IEC:1999 – 15 –
2.18
terminal
a conductive part provided for the connection of a conductor to an accessory
2.18.1
pillar terminal
a terminal in which the conductor is inserted into a hole or cavity, where it is clamped under the
shank of the screw or screws. The clamping pressure may be applied directly by the shank of
the screw or through an intermediate clamping member to which pressure is applied by the
shank of the screw (see figure 14a)
2.18.2
screw terminal
a terminal in which the conductor is clamped under the head of the screw. The clamping
pressure may be applied directly by the head of the screw or through an intermediate part,
such as a washer, clamping plate or anti-spread device (see figures 14b and 14c)
2.18.3
stud terminal
a terminal in which the conductor is clamped under a nut. The clamping pressure may be
applied directly by a suitably shaped nut or through an intermediate part, such as a washer,
clamping plate or anti-spread device (see figure 14d)
2.18.4
saddle terminal
a terminal in which the conductor is clamped under a saddle by means of two or more screws
or nuts (see figure 14e)
2.18.5
lug terminal
a screw terminal or a stud terminal, designed for clamping a cable lug or bar by means of a
screw or nut (see figure 14f)
2.18.6
mantle terminal
a terminal in which the conductor is clamped against the base of a slot in a threaded stud by
means of a nut. The conductor is clamped against the base of the slot by a suitably shaped
washer under the nut, by a central peg if the nut is a cap nut, or by equally effective means for
transmitting the pressure from the nut to the conductor within the slot (see figure 14g)
2.19
clamping unit
the part of a terminal necessary for the clamping and the electrical connection of the conductor
2.20
conditional short-circuit current
the prospective current that an accessory, protected by a specified short-circuit protective
device, can satisfactorily withstand for the total operating time of that device under specified
conditions of use and behaviour
NOTE – This definition differs from IEV 441-17-20 by broadening the concept of current-limiting device into a short-
circuit protective device, the function of which is not only to limit the current.

60309-1  IEC:1999 – 17 –
2.21
cap
a part separated or attached, which may be used to provide the degree of protection of a plug
or appliance inlet when it is not engaged with a socket-outlet or connector
2.22
lid
a means to ensure the degree of protection on a socket-outlet or a connector
3 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60309. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of IEC 60309 are encouraged to investigate the possibility of applying the
most recent editions of the normative documents indicated below. For undated references, the
latest edition of the normative document referred to applies. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60050-441:1984, International Electrotechnical Vocabulary (IEV) – Chapter 441:
Switchgear, controlgear and fuses
IEC 60083:1997, Plugs and socket-outlets for domestic and similar general use standardized in
member countries of IEC
IEC 60112:1979, Method for determining the comparative and the proof tracking indices of solid
insulating materials under moist conditions
IEC 60227, (all parts) Polyvinyl chloride insulated cables of rated voltages up to and including
450/750 V
IEC 60228:1978, Conductors of insulated cables
IEC 60245-4:1994, Rubber insulated cables – Rated voltages up to and including 450/750 V –
Part 4: Cords and flexible cables
IEC 60269-1:1986, Low-voltage fuses – Part 1: General requirements
IEC 60269-2:1986, Low-voltage fuses – Part 2: Supplementary requirements for fuses for use
by authorized persons (fuses mainly for industrial application) – Sections I to III
IEC 60320, (all parts) Appliance couplers for household and similar general purposes
IEC 60529:1989, Degrees of protection provided by enclosures (IP code)
IEC 60664-1:1992, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 60695-2-1:1994, Fire hazard testing – Part 2: Test methods
IEC 60947-3:1990, Low-voltage switchgear and controlgear – Part 3: Switches, disconnectors,
switch-disconnectors and fuse-combination units

60309-1  IEC:1999 – 19 –
4 General
4.1 General requirements
Accessories shall be so designed and constructed that in normal use their performance is
reliable and without danger to the user or surroundings.
Unless otherwise stated, the normal use environment in which the devices complying with this
standard are normally used is pollution degree 3 according to IEC 60664-1.
If other pollution degrees are needed, creepage and clearance distances have to be in
accordance with IEC 60664-1. The comparative tracking index (CTI) value shall be evaluated
in accordance with IEC 60112.
In general, compliance is checked by carrying out all the tests specified.
4.2 General notes on tests
4.2.1 Tests according to this standard are type tests. If a part of an accessory has previously
passed tests for a given degree of severity, the relevant type tests shall not be repeated if the
severity is not greater.
4.2.2 Unless otherwise specified, the samples are tested as delivered and under normal
conditions of use, at an ambient temperature of (20 ± 5) °C; the tests are made at rated
frequency.
4.2.3 Unless otherwise specified, the tests are carried out in the order of the clauses of this
standard.
4.2.4 Three samples are subjected to all the tests, except if necessary for the test of clause
29 where one new additional sample is tested. If, however, the tests of clauses 20, 21 and 22
have to be made with both d.c. and a.c., the tests with a.c. are made on three additional
samples.
4.2.5 Accessories are deemed to comply with this standard if no sample fails in the complete
series of appropriate tests. If one sample fails in a test, that test and those preceding which
may have influenced the test result are repeated on another set of three samples, all of which
shall then pass the repeated tests.
NOTE – In general, it will only be necessary to repeat the test which caused the failure, unless the sample fails in
one of the tests of clauses 21 and 22, in which case the tests are repeated from that of clause 20 onwards.
The applicant may submit, together with the first set of samples, the additional set which may be wanted should one
sample fail. The testing station will then, without further request, test the additional samples and will reject only if a
further failure occurs. If the additional set of samples is not submitted at the same time, the failure of one sample
will entail a rejection.
4.2.6 When the tests are carried out with conductors, they shall be copper and comply with
IEC 60227, IEC 60228 [clause 2, solid (class 1), stranded (class 2), flexible (class 5)] and
IEC 60245-4, as accessories according to this standard are intended to be connected to cables
with copper or copper-alloy conductors only.

60309-1  IEC:1999 – 21 –
5 Standard ratings
5.1 Preferred rated operating voltage ranges and voltages are:
20 V to 25 V 380 V to 415 V
40 V to 50 V 440 V to 460 V
100 V to 130 V 480 V to 500 V
200 V to 250 V 600 V to 690 V
277 V
5.2 Preferred rated currents are given in the following table:
Table 1
Series I Series II
A A
16 20
32 30
63 60
125 100
250 200
6 Classification
6.1 Accessories are classified:
6.1.1 according to purpose: plugs, socket-outlets, connectors, appliance inlets;
6.1.2 according to degrees of protection:
– either in accordance with IEC 60529;
– or according to degrees of protection against moisture:
– splashproof accessories;
– watertight accessories.
For new designs, degrees of protection according to IEC 60529 shall be used with a minimum
degree of protection of IP23.
6.1.3 according to earthing facilities:
– accessories without earthing contact;
– accessories with earthing contact;
6.1.4 according to the method of connecting the cable:
– rewirable plugs and connectors;
– non-rewirable plugs and connectors;

60309-1  IEC:1999 – 23 –
6.1.5 according to interlocking facilities:
– accessories without interlock, with or without integral switching device;
– accessories with mechanical interlock;
– accessories with electrical interlock.
7 Marking
7.1 Accessories shall be marked with:
– rated current(s) in amperes;
– rated operating voltage(s) or range(s) in volts;
– symbol for nature of supply, if the accessory is not intended for both a.c. and d.c., or is
intended for a.c. with frequencies other than 50 Hz or 60 Hz, or if the rating is different for
alternative current and direct current;
– rated frequency if exceeding 60 Hz;
– either the name or trade mark of the manufacturer or of the responsible vendor;
– type reference, which may be a catalogue number;
– symbol for degree of protection, as applicable;
– symbol indicating the position of the earthing contact or the means used for
interchangeability, if any.
NOTE – Optionally, the insulation voltage may be marked.
Compliance is checked by inspection.
7.2 When symbols are used, they shall be as follows:
A . amperes
V . volts
Hz . hertz
.............................................. alternating current
.............................................. direct current
(preferred) or . earth
(one drop in a triangle) . splashproof construction6
66 (two drops) . watertight construction
IPXX (relevant figures) . degree of protection according to IEC 60529
Where IP code according to IEC 60529 is used, the two characteristic numerals (XX) shall be
specified (see also 18.2).
Marking of degree of protection on plugs and appliance inlets is only valid when in engagement
with a complementary accessory or with an attached cap, if any.

60309-1  IEC:1999 – 25 –
For the marking of rated current(s) and rated operating voltage(s) or range(s), figures may be
used alone.
The figure for d.c. rated operating voltage, if any, shall then be placed before the figure for the
a.c. rated operating voltage, and separated from it by a line or a dash.
Compliance is checked by inspection.
7.3 For socket-outlets and appliance inlets, the marking for rated current, nature of supply, if
necessary, and either the name or trade mark of the manufacturer or the responsible vendor
shall be on the main part, on the outside of the enclosure, or on the lid, if any, if the latter
cannot be removed without the aid of a tool.
Except for flush-type socket-outlets and appliance inlets, these markings shall be easily
discernible when the accessory is mounted and wired as in normal use, if necessary after it has
been removed from the enclosure. The marking, if any, for the insulation voltage shall be on
the main part; it shall not be visible when the accessory is mounted and wired as in normal use.
The marking for rated operating voltage, type reference, the symbol for degree of protection, if
required, and the symbol indicating the position of the earthing contact or the means used for
interchangeability, if any, shall be on a place which is visible after installation of the accessory,
on the outside of enclosure or on the lid, if any, if the latter cannot be removed without the aid
of a tool.
With the exception of the type reference, these markings shall be easily discernible when the
accessory is mounted and wired as in normal use.
Compliance is checked by inspection.
NOTE – The term "main part" of a socket-outlet or an appliance inlet means the part carrying the contacts.
The type reference may be marked on the main part.
The marking for rated current, nature of supply, rated operating voltage and the name or trade
mark of the manufacturer or the responsible vendor, may be repeated on the lid, if any.
7.4 For plugs and connectors, the marking specified in 7.1, with the exception of the marking
for insulation voltage, if any, shall be easily discernible when the accessory is wired ready for
use.
The marking for insulation voltage, if any, shall be on the main part; it shall not be visible when
the accessory is mounted and wired as in normal use.
NOTE – The term "ready for use" does not imply that the plug or connector is in engagement with its
complementary accessory.
NOTE – The term "main part" of a plug or a connector means the part carrying the contacts.
Compliance is checked by inspection.

60309-1  IEC:1999 – 27 –
7.5 For rewirable accessories, the contacts shall be indicated by the symbols:
– for three-phase, the symbols L1, L2, L3, or 1, 2, 3 for the phases, N for neutral, if any, and
the symbol or for earth;
– for two-pole, which may be used for both a.c. and d.c., one symbol for one of the live poles
and the symbol or for earth, if any;
– for a period of time the marking R1, S2, T3 may be used instead of L1, L2, L3.
These symbols shall be placed close to the relevant terminals; they shall not be placed on
screws, removable washers or other removable parts.
NOTE – The terminals for pilot conductors are not required to be indicated.
The figures used with the letters may be written as an index. It is recommended that where practicable the
symbol , should be used.
Compliance is checked by inspection.
7.6 Marking shall be indelible and easily legible.
Compliance is checked by inspection and by the following test:
After the humidity treatment of clause 18, the marking is rubbed vigorously by hand for 15 s
with a piece of cloth soaked in water and again for 15 s with a piece of cloth soaked with
petroleum spirit.
Special attention is paid to the marking of the name or trade mark of the manufacturer or the
responsible vendor and to that of the nature of supply, if any.
NOTE – A special test for checking the indelibility of these markings is under consideration.
7.7 If, in addition to the marking prescribed, the rated operating voltage is indicated by means
of a colour, the colour code shall be as shown in table 2. An indicating colour, if different from
that of the enclosure, shall be used only if it can be easily distinguished.
Table 2
1) 2)
Rated operating voltage Colour
V
20 to 25 Violet
40 to 50 White
100 to 130 Yellow
200 to 250 Blue
380 to 480 Red
500 to 690 Black
1)
For frequencies over 60 Hz up to and including 500 Hz, the
colour green may be used, if necessary, in combination with the
colour for the rated operating voltage.
2)
In countries where accessories of series II current ratings are
used, the colour orange is reserved for 125/250 V a.c. and the
colour grey is reserved for 277 V a.c. accessories.

60309-1  IEC:1999 – 29 –
8 Dimensions
8.1 Accessories shall comply with the appropriate standard sheets, if any.
8.2 It shall not be possible to engage plugs or connectors with socket-outlets or appliance
inlets having different ratings, or having different contact combinations.
In addition, the design shall be such that improper connections shall not be possible between:
– the earth and/or pilot plug-contact and a live socket-contact, or a live plug-contact and the
earth and/or pilot socket-contact;
– the phase plug-contacts and the neutral socket-contact, if any;
– the neutral plug-contact and a phase socket-contact.
Compliance is checked by inspection.
8.3 It shall not be possible to make single-pole connections between plugs and socket-outlets
or connectors, or between appliance inlets and connectors or socket-outlets.
Plugs and appliance inlets shall not allow improper connections with socket-outlets complying
with IEC 60083 or with connectors complying with IEC 60320.
Socket-outlets and connectors shall not allow improper connections with plugs complying with
IEC 60083 or with appliance inlets complying with IEC 60320.
Improper connections include single-pole connections and other connections which do not
comply with the requirements for protection against electric shock.
Compliance is checked by inspection.
9 Protection against electric shock
9.1 Accessories shall be so designed that live parts of socket-outlets and connectors, when
they are wired as in normal use, and live parts of plugs and appliance inlets, when they are in
partial or complete engagement with the complementary accessories, are not accessible.
In addition, it shall not be possible to make contact between a contact of a plug or appliance
inlet and a contact of a socket-outlet or connector while any contact is accessible.
Compliance is checked by inspection and, if necessary, by a test on the sample wired as in
normal use.
60309-1  IEC:1999 – 31 –
The standard test finger shown in figure 2 is applied in every possible position, an electrical
indicator, with a voltage not less than 40 V, being used to show contact with the relevant part.
NOTE – The neutral contact and pilot contacts of socket-outlets and connectors are deemed to be live parts.
9.2 Accessories with earthing contact shall be so designed that:
– when inserting the plug or connector, the earth connection is made before the phase
connections and neutral, if any, are made;
– when withdrawing the plug or connector, the phase connections and neutral, if any, are
broken before the earth connection is broken.
9.3 It shall not be possible to inadvertently assemble the part carrying plug contacts into the
enclosure of a socket-outlet or connector.
Compliance is checked by manual test.
10 Provision for earthing
10.1 Accessories with earthing contact shall be provided with an earthing terminal. Metal-clad
fixed accessories with an internal earthing terminal can, in addition, be provided with an
external earthing terminal, which, except for flush type socket-outlets, shall be visible from the
outside.
Earthing contacts shall be directly and reliably connected to the earthing terminals, except that
the earthing terminal of socket-outlets incorporated in the output circuit of an isolating
transformer shall not be connected.
Compliance is checked by inspection.
10.2 Accessible metal parts of accessories with earthing contact, which may become live in
the event of an insulation fault, shall be reliably connected to the internal earthing terminal(s)
by construction.
NOTE – For the purpose of this requirement, screws for fixing bases, covers and the like are not deemed to be
accessible parts which may become live in the event of an insulation fault.
If accessible metal parts are screened from live parts by metal parts which are connected to an earthing terminal or
earthing contact, or if they are separated from live parts by double insulation or reinforced insulation, they are not,
for the purpose of this requirement, regarded as likely to become live in the event of an insulation fault.
Compliance is checked by inspection and by the following test:
A current of 25 A derived from an a.c. source having a no-load voltage not exceeding 12 V is
passed between the earthing terminal and each of the accessible metal parts in turn.
The voltage drop between the earthing terminal and the accessible metal part is measured, and
the resistance calculated from the current and this voltage drop.

60309-1  IEC:1999 – 33 –
In no case shall the resistance exceed 0,05 Ω.
NOTE – Care should be taken that the contact resistance between the tip of the measuring probe and the metal
part under test does not influence the test results.
10.3 Earthing contacts shall be capable of carrying a current equal to that specified for the
phase contacts without overheating.
Compliance is checked by the test of clause 22.
10.4 Earthing contacts shall be so shrouded or guarded that they are protected against
mechanical damage.
Compliance is checked by inspection.
NOTE – This requirement precludes the use of side earthing contacts.
Table 3 – Size for connectable conductors
Rating of External earthing
1)
Internal connection
the accessory connection if any
Flexible cables for plugs
Voltage Current
and connectors Solid or stranded cables
2)
for socket-outlets
Solid or stranded cables
V A
2)
for appliance inlets
2 3) 2 3) 2 3)
Series I Series II mm AWG/MCM mm AWG/MCM mm AWG/MCM
Not 16 20 4to10 12 to 8 4to10 12 to 8 – –
exceeding 50 32 30 4to10 12 to 8 4to10 12 to 8 – –
16 20 1to 2,5 16 to 12 1,5 to 4 16 to 12 6 10
32 30 2,5 to 6 14 to 10 2,5 to 10 14 to 8 10 8
63 60 6to16 10 to 6 6to25 10 to 4 25 4
Exceeding 50
125 100 16 to 50 6to 2 25 to 70 4to 0 25 4
4)
250 200 70 to150 00 to 0000 70 to 185 00 to 250 25 4
1)
Terminal for pilot conductors, if any, shall allow the connection of conductors having the same nominal cross-
sectional areas as the internal terminals of 16 A accessories having rated operating voltages exceeding 50 V.
2)
Classification of conductors: according to IEC 60228.
3) 2
The nominal cross-sectional areas of conductors are given in square millimetres (mm ). AWG/MCM values are
considered as equivalent to mm for the purpose of this standard.
AWG: American Wire Gauge is a system of identifying wires in which the diameters are in geometric progression
between size 36 and size 0000.
MCM: Mille Circular Mils denotes circle surface unit. 1 MCM = 0,5067 mm .
4) 2
150 mm for 200 A accessories of series II.
11 Terminals
11.1 Rewirable accessories shall be provided with terminals in which connection is made by
means of screws, nuts or equally effective devices.
Compliance is checked by inspection.
NOTE – Requirements for screwless terminals are under consideration.

60309-1  IEC:1999 – 35 –
11.2 Parts of terminals, other than screws, nuts, washers, stirrups, clamping plates and the
like, shall be either of:
– copper;
– an alloy containing at least 58 % copper for parts that are worked cold or at least 50 %
copper for other parts;
– or other metal not less resistant to corrosion than copper and having mechanical properties
no less suitable.
Steel screws shall be adequately protected against corrosion.
Compliance is checked by inspection and by chemical analysis.
NOTE – A relaxation of the requirement for parts of terminals is under consideration.
11.3 If the body of an earthing terminal is not part of the metal frame or housing of the
accessory, the body shall be of material as prescribed in 11.2 for parts for terminals. If the
body is part of the metal frame or housing, the clamping screw or nut shall be of such material.
If the body of the earthing terminal is part of a frame or housing of aluminium or aluminium
alloy, precautions shall be taken to avoid the risk of corrosion resulting from contact between
copper and aluminium or its alloys.
NOTE – The requirement regarding the avoidance of the risk of corrosion does not preclude the use of adequately
coated metal screws or nuts.
More detailed requirements are under consideration.
Compliance is checked by inspection and by chemical analysis.
NOTE – A test for determining the resistance to corrosion is under consideration.
11.4 Terminals shall provide for the connection of copper or copper-alloy conductors having
nominal cross-sectional areas as shown in table 3.
For terminals other than lug terminals, compliance is checked by the following test and by the
tests of 11.7, 11.8 and 11.9.
Gauges as specified in figure 13, having a measuring section for testing the insertability of the
maximum specified cross-sectional area of table 3, shall be able to penetrate into the terminal
aperture under their own weight to the designated depth of the terminal.
For pillar terminals in which the end of a conductor is not visible, the hole to accommodate
the conductor shall have a depth such that the distance between the bottom of the hole and the
last screw will be equal to at least half the diameter of the screw, and in any case not less
than 1,5 mm.
Compliance is checked by inspection.
For terminals complying with figure 14f, the lug shall accept conductors having nominal cross-
sectional areas within the appropriate range specified in table 3.
Terminals that cannot be checked by the gauges specified in figure 13 are tested by suitably
shaped gauges having the same cross-section as those of the appropriate gauges given in
figure 13.
60309-1  IEC:1999 – 37 –
11.5 Terminals shall have appropriate mechanical strength.
Screws and nuts for clamping shall have an ISO thread or a thread comparable in pitch and
mechanical strength.
NOTE – Provisionally, Sl, BA and UN threads are considered as being comparable in pitch and mechanical
strength.
Compliance is checked by inspection, measurement and the test of 25.1. In addition to the
requirements of 25.1, the terminals shall not have undergone changes after the test that
adversely affect their future use.
11.6 Terminals shall be properly fixed to the accessory and shall not work loose when the
clamping screws or nuts are tightened or loosened.
Screws and nuts for clamping the conductors shall not serve to fix any other component.
NOTE – The clamping means for the conductor may be used to stop rotation or displacement of the plug or socket
contacts.
Compliance is checked by inspection and, if necessary, by the test of 25.1.
NOTE – These requirements do not preclude terminals that are floating or terminals so designed that rotation or
displacement of the terminal is prevented by the clamping screw or nut, provided that their movement is
appropriately limited and does not impair the correct operation of the accessory.
Terminals may be prevented from working loose by fixing with two screws, by fixing with one screw in a recess such
that there is no appreciable play, or by other suitable means.
Covering with sealing compound without other means of locking is not deemed to be sufficient. Self-hardening
resins may, however, be used to lock terminals which are not subject to torsion in normal use.
11.7 Terminals shall be so designed that they clamp the conductor between metal surfaces
with sufficient contact pressure and without damage to the conductor.
Compliance is checked by inspection and the type tests of the terminals of 11.8 and 11.9,
applied to three separate terminals.
11.8 First test
Verification is made successively with conductors of the largest and smallest cross-sectional
areas specified in table 3, using class 1 or class 2 conductors for terminals of socket-outlets or
appliance inlets and class 5 conductors for terminals of plugs or connectors.
The conductors shall be connected to the clamping unit, and the clamping screws or nuts
tightened to two-thirds of the torque indicated in table 15; unless the torque is specified by the
manufacturer on the product or in an instruction sheet.
Each conductor is subjected to a pull according to the value in table 4-1, exerted in the
opposite direction to that in which the conductor was inserted. The pull is applied without jerks
for 1 min. The maximum length of the test conductor shall be 1 m.
During the test the conductor shall not slip out of the terminal nor shall it break at, or in, the
clamping unit.
60309-1  IEC:1999 – 39 –
Table 4-1
Nominal cross-sectional area Pulling force
mm N
1 30
1,5 40
2,5 50
4 50
6 60
10 80
16 90
25 100
50 140
70 160
150 220
185 240
11.9 Second test
This test is carried out first with the smallest cross-sectional area and then with the largest
cross-sectional area of the relevant values in table 3 for class 1 (up to and including 4 mm )
class 2 and class 5 conductors. The clamping screws or nuts are tightened with the torque
according to table 15, unless the torque is specified by the manufacturer on the product or in
an
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